10. Patients (during catheterization) with uncorrectable hypercarbia with pCO2 >55 mm Hg; patients with uncorrectable acidemia with pH <7.34; patients in active pain or distress; unconscious or mechanically ventilated patients; patients with unstable systemic or pulmonary blood flow; systemic arterial or pulmonary artery pressures or hematocrit (change of > 25% during catheterization); unstable cardiac rhythm dissimilar to baseline cardiac rhythm during physical examination assessments for the entire duration of the catheterization excepting nonsustained arrhythmia; patients with documented or recognized air embolism, hemorrhage, cardiac, cerebral or peripheral organ ischemia occurring during or immediately preceding the catheterization.